Circular details

Control of Methicillin-Resistant Staphylococcus Aureus (MRSA) and Epidemic MRSA (EMRSA) in Hospitals

Document ID:

Operational Circular OP 1922/05

Date of issue:

Thursday, 24 February 2005

Status:

NO LONGER APPLICABLE

File number(s):

02-05549

Description:

Acquisition of MRSA is a potential risk to all patients, but infections with MRSA are of particular significance to patients undergoing surgical procedures. It is important to prevent MRSA from becoming established in hospital wards where there are patients undergoing these high-risk procedures.

Control of Methicillin-Resistant Staphylococcus Aureus (MRSA) and Epidemic MRSA (EMRSA) in Hospitals

It should be noted that in Western Australia admission to hospital must not be denied or delayed solely on the basis of a patient's MRSA status.

1. INTRODUCTION

Staphylococcus aureus (S. aureus) is carried in the nostrils of approximately 30% of healthy people, but can invade the body through broken skin, especially through surgical wounds. Invasive infection may cause a wide range of clinical disease, including cellulitis, bacteraemia or osteomyelitis.

Methicillin-resistant S. aureus (MRSA) are resistant to all beta-lactam antibiotics, including penicillins and cephalosporins. MRSA are not more or less virulent than methicillin-susceptible strains, but MRSA infections are more difficult to treat because the number of effective antibiotics is reduced. MRSA currently comprise 10% to 30% of all isolates of S. aureus in Western Australia (WA) and, of these, around 90% are acquired in the community.

Acquisition of MRSA is a potential risk to all patients, but infections with MRSA are of particular significance for patients undergoing surgical procedures, especially the implantation of prosthetic material. It is important to prevent MRSA from becoming established in hospital wards where there are patients undergoing these high-risk procedures.

All new isolates of MRSA in WA are sent to Royal Perth Hospital for typing by the Gram-positive Bacteria Typing and Research Unit (GPTU). When a strain that has caused outbreaks in hospitals previously is identified, the laboratory notifies the hospital which the isolate came from. The hospital infection control staff are responsible for assessing the situation and, where necessary, implementing infection control measures to prevent dissemination of the MRSA.

2. DEFINITIONS

2.1 Methicillin-resistant Staphylococcus aureus (MRSA)

MRSA are resistant to methicillin (and consequently to all other beta-lactam antibiotics). For the purposes of infection control management, they can be divided into epidemic (EMRSA) and non-epidemic strains (MRSA).

2.2 Epidemic strains of MRSA (EMRSA)

Epidemic strains of MRSA are strains that have demonstrated the potential to cause outbreaks in health care facilities.

2.3 MRSA Colonisation or Infection

2.3.1 MRSA Colonisation: Detection of MRSA from a site which shows no physical sign of infection.

2.3.2 MRSA Infection: Invasion of the host with the production of inflammation and/or bacteraemia at the site of infection.

2.4 MRSA Carrier Status

2.4.1 MRSA Active Carrier: A person is an active carrier of MRSA when the organism has been isolated from a clinical specimen or by screening, on more than one occasion.

2.4.2 MRSA Inactive Carrier: A previously active carrier becomes inactive when one extended set of swabs, taken from the sites specified in Section 5.1, at least 1 week after cessation of antistaphylococcal treatment, are negative for MRSA.If the patient is on antibiotics prior to clearance, consultation should be sought with an Infectious Diseases Physician or Microbiologist.

2.4.3 MRSA Cleared Carrier: A previously active carrier (not currently on antibiotic treatment) who returns 2 extended sets of negative swabs collected on the same or different days, at least 3 months after last returning positive swabs. If previously treated for MRSA, the 3 month interval dates from cessation of treatment. NOTE: Some antibiotic treatments during the 3 month period, e.g. penicillins and cephalosporins, do not preclude clearance. Where necessary, an Infectious Diseases Physician or Microbiologist should be consulted.

2.4.4 MRSA Transient Carrier: A person is a transient carrier of MRSA when the organism has been isolated on only 1 occasion and 1 subsequent full set of screening swabs is negative.

2.5 MRSA Contact: Any person who has been:

An in-patient of a hospital, or a resident in a residential care facility (RCF) outside WA in the previous 12 months.

New or returning staff member who has provided clinical care in a non-WA hospital or non-WA RCF in the previous 12 months.

A room-mate of an active EMRSA carrier who was identified during a EMRSA outbreak occurring in the previous 12 months, and who was discharged from hospital before being screened.

3.1.1 All staff MRSA contacts (see 2.5) must be screened as per Staff MRSA Screening Set (see Appendix 4) before initial employment in a WA hospital. This applies to all prospective hospital staff members who will have contact with patients ? medical, nursing and ancillary staff alike, and to staff employed by Agency or Locum Services.

3.1.2 All prospective staff from outside of WA should be advised that they will be required to be screened in WA prior to employment.

3.2 Management of Staff MRSA Carriers

3.2.1 Staff carriers detected by pre-employment screening

All staff found to be carrying EMRSA by pre-employment screening should be given topical decolonisation treatment in consultation with hospital infection control staff, and should be followed up until they are cleared. For carriers of non-epidemic MRSA, advice on this matter should be sought from the hospital infection control staff.

Health Care Workers (HCW) must have a set of MRSA screening swabs weekly for 10 weeks following completion of the treatment. Those who relapse during the 10 week follow-up period must be re-treated and followed-up until they have been negative for 10 weeks after completion of a course of treatment.

3.2.2 Staff carriers detected during employment as a result of infection control investigations

Carriers of EMRSA should be given decolonisation treatment in consultation with hospital infection control staff.

For carriers of non-epidemic MRSA, advice should be sought from the hospital infection control staff.

3.2.3 Commencement or return to work

Staff may commence or return to work the day after starting decolonisation treatment, provided they do not have hand lesions, an upper respiratory tract infection or an active exfoliative skin condition, e.g. active dermatitis, eczema or psoriasis.

4. SCREENING AND MANAGEMENT OF INPATIENTS/CONTACTS

4.1 Risk Assessment

An MRSA risk assessment should be considered when admitting patients into acute care settings.

As a minimum, screening should be performed on patients coming from long term residential care facilities and those patients who have been contacts of an epidemic strain outbreak (MicroW alert).

4.2 Screening In-Patients/Contacts for MRSA

All patients identified to have a high MRSA risk should be routinely screened with a single short set (see Appendix 4.1) of MRSA screening swabs.

All patients who are MRSA contacts (Section 2.5) should be screened with a single short set (see Appendix 4.1) of MRSA screening swabs.

4.3 Management of Hospital In-Patient MRSA Carriers and Contacts

4.3.1 Active EMRSA carriers should be nursed with Additional Precautions (Appendix 3). When single rooms are not available, EMRSA carriers should be cohorted when there are multiple cases of the same strain.

4.3.2 A patient known to have been colonised with EMRSA in the previous 3 months, but having negative swabs, is an "inactive carrier" and should be nursed in a single room with Standard Precautions. However, a patient in this category given an antibiotic has a high probability of re-establishing EMRSA carriage and should be nursed with Additional Precautions (Appendix 3).

4.3.3 Contacts admitted pending the results of MRSA screening should be nursed in a single room with Standard Precautions, except for the circumstances described in sections 5.1.1 to 5.1.3.

4.3.4 For follow-up and clearance of patients see Section 5.

4.3.5 For carriers of non-epidemic MRSA, advice should be sought from the hospital infection control staff.

5. CLEARANCE OF EMRSA CARRIERS

5.1 Clearance

Caution - Clearance of EMRSA carriers may be difficult in patients with invasive devices, unhealed wounds and exfoliated skin conditions.

5.1.1 Clearance of EMRSA Transient Carrier: An EMRSA carrier who has had only one EMRSA isolation is cleared when 1 subsequent extended set of MRSA swabs is negative. (See Appendix 4.3)

5.1.2 Clearance of EMRSA Inactive Carrier: (See Appendix 4). An inactive EMRSA carrier should have an extended set of swabs taken at weekly intervals for 3 months, or 2 full sets collected on the same or different days at least 3 months after the last positive swab. If all swabs are negative the person is cleared.

5.1.3 Clearance of Active Carrier: An active carrier becomes inactive when one extended set of swabs is negative and is cleared when 2 further sets (collected on the same or different days) 3 or more months later are negative.

6. TERMINAL CLEANING

Rooms that have been occupied by any patient with EMRSA should be cleaned as specified in Appendix 5.

7. TRANSFER OF EMRSA CARRIERS BETWEEN HOSPITALS

The following precautions must be taken:

7.1 If the patient has carried EMRSA while in hospital, the receiving hospital must be informed of the patient's EMRSA status prior to transfer.

7.2 The patient should have all wounds or ulcers covered with non-porous dressings and a whole body antiseptic wash (Appendix 1) applied at the time of transfer between hospitals. This reduces dispersion.

A patient carrying EMRSA must NOT have their transfer between hospitals refused or delayed because of their EMRSA carrier status.

All WA microbiology laboratories are directed to send all MRSA isolates from new carriers to the Gram Positive Typing Unit, Royal Perth Hospital Microbiology Department, together with the information required for each newly detected carrier.

MRSA is a notifiable condition, but referral of an isolate to RPH will be considered appropriate notification. Any additional clinical information required MUST be provided by the attending physician.

9. MICRO-ALERT

The Micro-Alert system is a computerised database of MRSA carriers.

The Micro-Alert system is currently only available in public hospitals in the Perth metropolitan area. It was devised to alert the hospital staff in the metropolitan public hospitals to persons who have been found to be EMRSA carriers.

The Microbiology Department at each of the WA Teaching Hospitals is responsible for adding or removing patients from the Micro-Alert System.

Goetz A, Muder R. The problem of methicillin-resistant Staphylococcus aureus: a critical appraisal of the efficacy of infection control procedures with a suggested approach for infection control programs. American Journal of Infection Control. 1992;20:80-84.